Default 802.1p Priority to Transmit Queue mapping

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Article ID: 7584 

Products
Matrix N-Series DFE
SmartSwitch 2000 2nd Generation
SmartSwitch 6000 2nd Generation
SmartSwitch 6000 3rd Generation
Matrix C1
Matrix E1
SecureStack C3, C2, B3, B2, A2
D-Series
G-Series
I-Series
Matrix X-Series
X-Pedition 

Protocols/Features
Policy
CoS
UPN 

Standards
802.1p 

Solution
Each of these products support a certain number of hardware-based transmit queues per port. Here are their default transmit queue mappings, based upon the following: 
  • If there is no Policy-based Class of Service, then an 802.1p Priority maps to a Transmit Queue.
  • If Policy-based Class of Service is active, then a Class of Service maps to a Priority of the same value, and maps either indirectly or directly to a Transmit Queue.

The 'set' commands equivalent to the stated 'show' commands would be used to adjust the default mappings shown. 

Unprioritized traffic uses a 802.1p Priority of 0. 
    Product           802.1p Priority/CoS    Transmit Queue

Matrix N; non-Policy Priority, 'show port priority-queue'
-4 or 8 queues- 0 4&8 Qs-> 1
Fast Ethernet ports 1 0
2 0
3 1
4 2
5 2
6 3
7 3
Matrix N; non-Policy Priority, 'show port priority-queue'
-4, 8, or 16 queues- 0 4 Qs-> 1 8&16 Qs-> 2
Gigabit ports 1 0 0
2 0 1
Note: Only 8 transmit 3 1 3
queues are available 4 2 4
on the 16Q blades, 5 2 5
without policy. 6 3 6
7 3 7
Matrix N; Policy CoS, 'show cos settings' and 'show cos reference txq'
0 4&8 Qs-> 0 16 Qs-> 0
1 0 2
2 1 4
3 1 6
4 2 8
5 2 10
6 3 12
7 3 14

SmartSwitch 2nd/3rd Gen; non-Policy & Policy, 'Traffic Class Information'
-4 queues- 0 1
1 0
2 0
3 1
4 2
5 2
6 3
7 3

Matrix C1; non-Policy & Policy permit no view or adjustment
-8 queues- 0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7

Matrix E1; non-Policy & Policy, 'show priority queue'
-4 queues- 0 1
1 0
2 0
3 1
4 2
5 2
6 3
7 3

SecureStack C3/C2/B3/B2/A2; non-Policy & Policy, 'show port priority-queue'
-6 queues- 0 1
1 0
Note: The A2 has no 2 0
Policy support and the 3 2
B2/B3 require licensing 4 3
for Policy use 5 4
6 5
7 5

D-Series; non-Policy & Policy, 'show port priority-queue'
-8 queues- 0 2
1 0
Note: Requires licensing 2 1
for Policy use 3 3
4 4
5 5
6 6
7 7

G-Series; non-Policy & Policy, 'show port priority-queue'
-6 queues- 0 1
1 0
2 0
3 2
4 3
5 4
6 5
7 5

I-Series; non-Policy & Policy, 'show port priority-queue'
-6 queues- 0 1
1 0
2 0
3 2
4 3
5 4
6 5
7 5

Matrix X; non-Policy Priority, 'show port priority-queue'
-8 queues- 0 2
1 0
2 1
3 3
4 4
5 5
6 6
7 7
Matrix X; Policy CoS, 'show port cos class-of-service'
0 2

X-Pedition; 'qos show priority-map all'
-4 queues- 0 Low
1 Low
2 Medium
3 Medium
4 High
5 High
6 Control
7 Control

See also: 7546, 5781, and 10791.
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